From: Chunyu Hu Date: Tue, 3 May 2016 11:34:34 +0000 (+0800) Subject: tracing: Don't display trigger file for events that can't be enabled X-Git-Tag: firefly_0821_release~176^2~4^2~46^2~47 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=8d2923930be15a5b295ace2029c76653dc4def13;p=firefly-linux-kernel-4.4.55.git tracing: Don't display trigger file for events that can't be enabled commit 854145e0a8e9a05f7366d240e2f99d9c1ca6d6dd upstream. Currently register functions for events will be called through the 'reg' field of event class directly without any check when seting up triggers. Triggers for events that don't support register through debug fs (events under events/ftrace are for trace-cmd to read event format, and most of them don't have a register function except events/ftrace/functionx) can't be enabled at all, and an oops will be hit when setting up trigger for those events, so just not creating them is an easy way to avoid the oops. Link: http://lkml.kernel.org/r/1462275274-3911-1-git-send-email-chuhu@redhat.com Fixes: 85f2b08268c01 ("tracing: Add basic event trigger framework") Signed-off-by: Chunyu Hu Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman --- diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index d202d991edae..996f0fd34312 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -2107,8 +2107,13 @@ event_create_dir(struct dentry *parent, struct trace_event_file *file) trace_create_file("filter", 0644, file->dir, file, &ftrace_event_filter_fops); - trace_create_file("trigger", 0644, file->dir, file, - &event_trigger_fops); + /* + * Only event directories that can be enabled should have + * triggers. + */ + if (!(call->flags & TRACE_EVENT_FL_IGNORE_ENABLE)) + trace_create_file("trigger", 0644, file->dir, file, + &event_trigger_fops); trace_create_file("format", 0444, file->dir, call, &ftrace_event_format_fops);